It’s a sweaty August morning on Pier 15 in Manhattan’s South Street Seaport, and I’m cracking a blood orange tangerine Spindrift with Bill Creelman. I feel a bit like Homer Simpson getting handed a beer by Duffman, given Creelman’s status in the world of seltzer. “If we’re being honest, yes, we do,” he says. Creelman’s six-can daily regimen includes an …